JP2017077165A - Charger control circuit, charger, charger control method, charger control program, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charger control circuit capable of reducing temperature rise of a battery, reduction of battery liquid, and the like, and to provide a charger, a charger control method, a charger control program, and a recording medium.SOLUTION: A charger control circuit 1 for controlling the operation of a charger 3 charging a battery 4 includes a current control section 10 for charging a battery while controlling the charging current value to a predetermined first current value, a current control release section 12 for releasing control of the charging current value when the charging voltage reaches predetermined voltage value, a voltage control section 14 for charging the battery 4 while holding the charging voltage at the voltage value after current control is released, and a voltage control release section 16 releasing the control for holding at the voltage value, when the charging current value of the battery 4 reaches a predetermined second current value lower than the first current value.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a charger control circuit, a charger, a charger control method, a charge control program, and a recording medium. In particular, the present invention relates to a charger control circuit, a charger, a charger control method, a charge control program, and a recording medium that can control a charging profile in stages.

  2. Description of the Related Art Conventionally, in order to control charging of a secondary battery, a charging control method for controlling a charging current interposed between the AC adapter and the secondary battery and flowing from the AC adapter to the secondary battery by turning on / off a charging control switch When the charging voltage of the secondary battery exceeds a reference voltage set for the secondary battery, a step of performing constant current charging for maintaining a predetermined current as a charging current, and when a predetermined condition is satisfied In addition, a charging control method including a step of performing constant voltage charging so that a charging voltage of a secondary battery becomes equal to a set reference voltage is known (for example, see Patent Document 1). According to the charging control method described in Patent Document 1, the charging time of the secondary battery can be shortened.

JP 2003-319568 A

  However, in the charge control method described in Patent Document 1, even if the charge voltage exceeds the reference voltage, the charge current is maintained at a predetermined current value and charging is continued, so the load on the battery is not reduced. In other words, it is not possible to reduce the progress of battery deterioration due to a decrease in battery fluid, a rise in battery temperature, or the like.

  Accordingly, an object of the present invention is to provide a charger control circuit, a charger, a charger control method, a charge control program, and a recording medium that can reduce a rise in battery temperature, a decrease in battery liquid, and the like.

  In order to achieve the above object, the present invention is a charger control circuit that controls the operation of a charger that charges a battery, and charges the battery by controlling the charging current value to a first predetermined current value. A current control unit that releases the control of the charging current value when the charging voltage reaches a predetermined voltage value; and after the current control is released, the charging voltage is set to a predetermined voltage value. A voltage control unit that holds and charges the battery, and a control that holds the battery at a predetermined voltage value when the charging current value of the battery reaches a predetermined second current value lower than the first current value. There is provided a charger control circuit including a voltage control canceling unit for canceling.

  The charger control circuit may further include a timer driving unit that drives a timer that stops charging after elapse of a predetermined time after canceling the control to maintain the voltage value.

  The charger control circuit may further include a maximum charging voltage control unit that preliminarily defines a maximum charging voltage of the battery and controls the charging voltage to be equal to or lower than the maximum value during charging of the battery.

  The charger control circuit may further include a charging stop unit that stops charging the battery when the charging current value does not reach a predetermined current value or less.

  In the charger control circuit, the battery may be used for an aerial work vehicle, a machine having power driven by electricity, or a special vehicle.

  The charger control circuit may further include a protection unit that stops the supply of power to the battery when the input voltage input to the battery is equal to or higher than a predetermined voltage.

  Further, in the charger control circuit, the protection unit sets the input voltage as an output voltage when the input voltage is equal to or lower than a predetermined first voltage, and the input voltage is equal to or higher than a second voltage higher than the first voltage. In the case where the output voltage is a step-down voltage obtained by reducing the input voltage according to the second voltage, and the step-down voltage is equal to or lower than a predetermined threshold voltage. It can also have a supply stop part which stops supply of electric power.

  Moreover, in order to achieve the said objective, this invention provides a charger provided with the charger control circuit in any one of said, and a switching power supply.

  In order to achieve the above object, the present invention provides a charger control method for controlling an operation of a charger for charging a battery, wherein the battery is controlled by controlling a charging current value to a predetermined first current value. A first charging step for charging the battery, a current control releasing step for releasing the control of the charging current value when the charging voltage reaches a predetermined voltage value, and a charging voltage set in advance after the current control releasing step. A second charging step for controlling the voltage value to charge and charging the battery; and when the battery charging current value reaches a predetermined second current value lower than the first current value. There is provided a charger control method including a voltage control release step of releasing the control held at the voltage value.

  In order to achieve the above object, the present invention provides a charging control program for a charger control circuit for controlling the operation of a charger for charging a battery, wherein the computer sets a first current value predetermined for the computer. A first charging function for charging the battery by controlling the charging current value; a current control releasing function for releasing control of the charging current value when the charging voltage reaches a predetermined voltage value; and control of the charging current value Is released, the charging voltage is controlled to be held at a predetermined voltage value, the second charging function for charging the battery, and the charging current value of the battery is lower than the first current value. There is provided a charge control program that realizes a voltage control release function for releasing control held at a predetermined voltage value when the second current value is reached.

  In order to achieve the above object, the present invention provides a computer-readable recording medium in which the above-described charging control program is recorded.

  According to the charger control circuit, the charger, the charger control method, the charge control program, and the recording medium according to the present invention, the charger control circuit, the charger, and the charge that can reduce the temperature rise of the battery, the decrease of the battery liquid, and the like. Device control method, charging control program, and recording medium can be provided.

It is a functional block diagram of the charger control circuit according to the present embodiment. It is a charge profile figure by the charger control circuit which concerns on this Embodiment. It is a flowchart of charge control of the charger which concerns on this Embodiment. It is a functional block diagram of a charger control circuit according to a modification of the present embodiment. It is a circuit diagram of the protection part used for the charger control circuit which concerns on the modification of this Embodiment.

[Embodiment]
FIG. 1 shows an example of an outline of a functional configuration of a charger control circuit according to an embodiment of the present invention.

[Outline of Charger Control Circuit 1 and Charger 3]
The charger control circuit 1 according to the present embodiment is switched by a control method of at least one of constant current charging by weak current, constant voltage charging by weak voltage, and / or free charging not controlled by weak current and weak voltage. This is a control circuit for charging the battery 4 by controlling the operation of the power source 2. The charger control circuit 1 controls the charging operation of the switching power supply 2 by combining a plurality of charging controls, and charges the battery 4 with an appropriate charging efficiency. The charger control circuit 1 is, for example, an aerial work vehicle, a machine having power driven by electricity (for example, an electric cleaner, a golf cart, an electric vehicle, etc.), or a special vehicle (for example, a rechargeable electric forklift, an automatic guided machine). The charging operation of the charger 3 for charging a battery 4 (for example, a lead storage battery) having a battery liquid used for a towing vehicle, a transport vehicle, or the like is controlled.

  The charger control circuit 1 according to the present embodiment performs charging of the battery 4 in a stepwise manner by a combination of a plurality of charging controls, so that the battery 4 can be prevented from being charged with a high current and / or a high voltage. . That is, the charger control circuit 1 can prevent the phenomenon that the current value during charging due to the heat generation of the battery 4 does not decrease, and as a result, can prevent the continuation of charging due to high voltage and high current. Thereby, the charger control circuit 1 can reduce the decrease in the battery fluid of the battery 4, the heat generation of the battery 4, the expansion of the battery case storing the battery 4, and / or the deterioration of the battery 4.

[Details of Charger Control Circuit 1 and Charger 3]
The charger 3 according to the present embodiment includes a charger control circuit 1 and a switching power supply 2 that controls the charging operation by the charger control circuit 1 and supplies power to the battery 4. The charger control circuit 1 that controls the operation of the charger 3 that charges the battery 4 includes a current control unit 10 that controls a charging current, a current control release unit 12 that releases current control by the current control unit 10, and a charging voltage. A voltage control unit 14 that controls the voltage, a voltage control release unit 16 that releases the voltage control by the voltage control unit 14, a timer drive unit 18 that stops the charging operation after a predetermined time has elapsed, and a rating of the battery 4 A charging maximum voltage control unit 20 that controls the charging voltage below the maximum value of the voltage and a charging stop unit 22 that stops charging the battery 4 when a predetermined condition is satisfied.

(Current control unit 10)
The current control unit 10 charges the battery 4 by controlling the charging current value to a predetermined first current value. For example, the first current value is set to a current value at which the temperature of the battery liquid does not substantially increase. As an example, the first current value is set to a current value lower than the capacity value of the battery 4 (that is, when the battery capacity is “X” Ah, the first current value is set to “Y” A). (The relationship between X and Y is X>Y> 0). The current control unit 10 controls the charging current to a weak current (that is, a current value lower than the capacity value) even when the voltage of the battery 4 is lower than when fully charged in the initial stage of charging.

(Current control release unit 12)
The current control cancellation unit 12 cancels the control of the charging current value when the charging voltage of the battery 4 has reached a predetermined voltage value. That is, the current control release unit 12 works on the current control unit 10 to release the control of the charging current value by the current control unit 10. After the current control canceling unit 12 cancels the control by the current control unit 10, the current value of the charging current in charging the battery 4 is not controlled, and the charging current is substantially free.

(Voltage control unit 14)
The voltage control unit 14 charges the battery 4 while holding the charging voltage of the battery 4 at a predetermined voltage value. For example, the voltage control unit 14 charges the battery 4 while holding the charging voltage at a predetermined voltage value after the control of the charging current by the current control unit 10 is released. In this case, the voltage value is set to a value lower than the rated voltage of the battery 4, for example.

(Voltage control release unit 16)
The voltage control canceling unit 16 cancels the control of the charging voltage value when the charging current of the battery 4 has reached a predetermined current value. That is, the voltage control release unit 16 works on the voltage control unit 14 to release the control of the charging voltage value by the voltage control unit 14. After the voltage control cancellation unit 16 cancels the control of the voltage value by the voltage control unit 14, the voltage value of the charging voltage in charging the battery 4 is not controlled, and the charging voltage is substantially free. For example, the voltage control release unit 16 is predetermined by the voltage control unit 14 when the charging current value of the battery 4 has reached a predetermined second current value lower than the first current value. Release the control to keep the voltage value constant.

(Timer drive unit 18)
The timer driving unit 18 drives a timer that stops the charging of the battery 4 after a predetermined time has elapsed. For example, the timer driving unit 18 is triggered by the fact that the control for holding the voltage value of the charging voltage by the voltage control unit 14 has been canceled by the voltage control canceling unit 16 or the charging current value has reached the second current value. Drive the timer as

(Maximum charging voltage controller 20)
The charging maximum voltage control unit 20 predefines a maximum value of the charging voltage of the battery 4 and controls the charging voltage to be equal to or lower than the maximum value during charging of the battery 4. The charging maximum voltage control unit 20 monitors the charging voltage from the start to the end of charging of the battery 4 and controls the charging voltage so that the charging voltage is equal to or lower than the maximum value.

(Charge stop unit 22)
The charging stop unit 22 forcibly stops the charging of the battery 4 when the charging current value of the battery 4 does not reach a predetermined current value or less. By causing the charging stop unit 22 to function, if the charging time becomes long due to deterioration or failure of the battery 4, that is, the charging current does not decrease due to the temperature rise of the battery 4, and the charging voltage does not increase. When the phenomenon occurs, the charging of the battery 4 can be automatically stopped. As a result, it is possible to prevent problems due to deterioration of the battery 4 and save electricity costs associated with charging. The time from the start of charging of the battery 4 until the charging current value reaches a predetermined current value or less is defined as a predetermined time (hereinafter referred to as “charging stop time”). The charging stop unit 22 stops charging when the charging current value does not reach a predetermined current value or less when the charging stop time has elapsed. This charging stop time can be appropriately set according to the type of the battery 4.

[Details of charger control method]
FIG. 2 shows an example of a charging profile of the battery by the charger control circuit according to the present embodiment. In FIG. 2, the X axis is a time axis, the right Y axis is an axis indicating a voltage value, and the left Y axis is an axis indicating a current value. In FIG. 2, the solid line is a graph showing a change in current value, and the alternate long and short dash line is a graph showing a change in voltage value. FIG. 3 shows an example of the flow of charging control of the charger according to the present embodiment.

First, the current control unit 10 controls the charging current to a first current value (hereinafter referred to as I ₁ ) and starts charging the battery 4 (Step 10 in FIG. 3). S ”). First current value I _1, as an example, is determined by selecting from a range of degree more than 25A below 14A. It is assumed that the charging start time is t ₀ and the voltage of the battery 4 at t ₀ is V ₁ . For example, the voltage V ₁ can be selected and determined from a range of about 28 V or more and 29.5 V or less. The current control unit 10 sets the voltage of the battery 4 to a predetermined voltage value (hereinafter referred to as V ₂ , where V ₁ <V ₂ is satisfied. Further, the rated maximum voltage of the battery 4 is set to V _max . _If, V ₂ satisfies the _{<V max.)} to reach, to continue charging while maintaining the charging current to _{I 1} (S15 of No). Then, when the voltage of the battery 4 reaches V ₂ (Yes in S15), the current control release unit 12 releases the control of the current value by the current control unit 10 (S20). Incidentally, the time when the voltage of the battery 4 reaches the V ₂ and t _1.

Then, the voltage control unit 14 controls the charging voltage to V ₂ and continues charging the battery 4 (S25). In the voltage control unit 14, the charging current is a predetermined second current value (hereinafter referred to as I ₂ , where I ₁ > I _2. I ₂ is, for example, a range of about 8A to 10A. It can be determined by selecting from.) to reach, to continue charging while maintaining the charging voltage V ₂ (No in S30). Then, the voltage control release unit 16, the current of the battery 4 when it reaches the _{I 2} (Yes in S30), and release of the control voltage value by the voltage controller 14 (S35). Incidentally, the time when the current of the battery 4 reaches the I ₂ and t _2. Time t ₂ later, the charger control circuit 1 continues to charge the battery 4 at a current value I ₂ following a low current value. Point in time t ₂ and later, the charging voltage is gradually increased with the progress of charging of the battery 4.

Then, the timer driver 18 starts driving from the time _{t 2} of the timer (S40). Timer-driven unit 18, when the predetermined time from the start of the driving of the timer has elapsed (e.g., time point t ₃ in FIG. 2) stops the charging of the battery 4 in. The time for which the timer driving unit 18 drives the timer can be selected and determined from a range of about 2 hours to 5 hours as an example.

Here, after the start of the driving of the timer, the charging voltage gradually increases as the charging continues. Therefore, if the rated maximum voltage of the battery 4 is _{V max,} the maximum charging voltage control unit 20, through the charging of the battery 4, and controls the charging voltage _{V max} or less, or the voltage _{V 3} lower than _{V max.} Voltage _{V 3,} as an example, can be determined by selecting from a range of degree more than 32V below 29V. The charging of the battery 4 is stopped when a predetermined time has elapsed. The charging stop unit 22 stops charging the battery 4 when charging the battery 4 and the state where the charging current does not reach the predetermined current value or lower continues for a predetermined time.

[Charge control program]
Each component included in the charger control circuit 1 according to the present embodiment shown in FIG. 1 executes a program (that is, a charge control program) in an arithmetic processing unit such as a central processing unit (CPU). That is, it can be realized by processing by software. It can also be realized by writing a program in advance as hardware as an electronic component such as an integrated circuit (IC). Software and hardware can be used together.

  The charge control program according to the present embodiment can be incorporated in advance in, for example, an IC or a ROM. The charge control program is a file in an installable or executable format, recorded on a computer-readable recording medium such as a magnetic recording medium, an optical recording medium, or a semiconductor recording medium, and provided as a computer program. You can also. The recording medium storing the program may be a non-transitory recording medium such as a CD-ROM or DVD. Furthermore, the charging control program can be stored in advance in a computer connected to a communication network such as the Internet, and can be provided by downloading via the communication network.

  The charge control program according to the present embodiment works on a CPU or the like to change the charger control circuit 1 to the current control unit 10, the current control release unit 12, the voltage control unit 14, and the voltage control described with reference to FIGS. 1 to 3. The release unit 16, the timer driving unit 18, the maximum charging voltage control unit 20, and the charging stop unit 22 are caused to function.

[Modification of Embodiment]
FIG. 4 shows an example of an outline of a functional configuration of a charger control circuit according to a modification of the embodiment of the present invention. The charger control circuit 1a according to the modified example has substantially the same configuration and function as the charger control circuit 1 except that it further includes a protection unit. Therefore, a detailed description is omitted except for differences.

  The charger control circuit 1a according to the modification detects whether or not the input voltage input from the switching power supply 2 to the battery 4 is equal to or higher than a predetermined voltage, and the input voltage is equal to or higher than the predetermined voltage. In some cases, a protection unit 24 for stopping the supply of power to the battery 4 is further provided. Specifically, the protection unit 24 sets the input voltage as the output voltage when the input voltage is equal to or lower than a predetermined first voltage, and the second when the input voltage is equal to or higher than the second voltage higher than the first voltage. When the step-down voltage is equal to or lower than the predetermined threshold voltage and the voltage adjustment unit 240 uses the step-down voltage with the input voltage lowered according to the voltage level as the output voltage, and supplies the power to the battery 4 A supply stop unit 242 for stopping the operation.

  For example, when the input voltage is equal to or lower than the first voltage, the voltage adjustment unit 240 outputs the input voltage as it is as the output voltage. On the other hand, when the input voltage is equal to or higher than the second voltage, the voltage adjustment unit 240 steps down the input voltage to a voltage lower than the second voltage. Then, the supply stop unit 242 stops the supply of power to the battery 4 in accordance with the voltage output from the voltage adjustment unit 240. For example, the supply stop unit 242 does not stop the supply of power to the battery 4 and is output from the voltage adjustment unit 240 when the voltage of the power output from the voltage adjustment unit 240 exceeds a predetermined threshold voltage. When the power voltage is equal to or lower than a predetermined threshold voltage, the supply of power to the battery 4 is stopped. Here, it is preferable that the voltage adjustment unit 240 steps down the second voltage to be equal to or lower than a predetermined threshold voltage. Thereby, according to the charger control circuit 1 a including the protection unit 24, it is possible to prevent an excessive voltage from being applied to the battery 4.

  FIG. 5 shows an example of a circuit diagram of a protection unit used in a charger control circuit according to a modification of the embodiment of the present invention. The main system 30 refers to a portion obtained by removing the protection unit 24 from the functional configuration block diagram of FIG.

For example, the protection unit 24 includes a circuit as shown in FIG. For example, below the first voltage (for example, AC110V), the specified current flows from the voltage V _rpl through the resistance of the _polyswitch 230 to the relay coil 236 and continuously operates. 30 operates continuously. On the other hand, when the voltage exceeds the first voltage, the voltage V _rpl rises and the voltage V _dv determined by the variable resistor 220, the resistor 222, the resistor 224, the resistor 226, and the resistor 228 also rises. Therefore, the Zener diode 232 and the resistor The current value with respect to 234 also increases, and the voltage _Vg increases. When the voltage V _g reaches the threshold between the SCR gate and cathode, between the anode and cathode of the SCR becomes conductive. As a result, the relay coil current from the voltage V _rpl to the poly switch 230 is cut off, so that the relay 238 is turned OFF. As a result, the supply of the AC input voltage in the overvoltage state is disconnected from the main system 30, so that the operation is safely stopped without causing damage or the like. In this case, since the thermistor resistance becomes an excessive value due to the positive direction thermistor effect of the _polyswitch 230, the overcurrent flowing through the V _{rpl -polyswitch} 230-SCR becomes SCR, diode 212, diode 214, diode 216, and diode 218. Prevents short circuit and burnout.

  Thus, by providing the protection unit 24, the charger control circuit 1a can be continuously operated as an example with an AC voltage of 110V or less, and a relay when overvoltage (over AC110V, about 220V or less, or over 220V). Since 238 is cut off, the battery 4 and the charger control circuit 1a can be prevented from being damaged.

(Effect of embodiment)
The charger control circuit 1 according to the present embodiment can control the charging current and / or the charging voltage step by step when charging the battery 4 and starts charging at a low current value. The battery 4 can be charged with an optimal charging profile according to the state. Thereby, the charger control circuit 1 can suppress the heat generation of the battery 4 and can suppress the decrease of the battery liquid. Therefore, according to the charger control circuit 1, it is possible to reduce labor costs and costs due to replenishment of the battery liquid and costs due to battery replacement due to deterioration of the battery 4.

  Moreover, since the charger control circuit 1 according to the present embodiment can control the charging current and / or the charging voltage when charging the battery 4, compared with the case where the setting of the charging current and / or the charging voltage is not changed. The voltage of the battery 4 is not forced to reach the rated maximum voltage. Therefore, the charger control circuit 1 according to the present embodiment charges the battery 4 immediately after the start of charging when the battery 4 is charged even when the voltage of the battery 4 decreases after the battery 4 is used. It is possible to prevent the current from becoming a high current. Therefore, according to the charger control circuit 1 according to the present embodiment, the battery 4 can be charged while suppressing the decrease in the battery liquid and the temperature rise of the battery 4, so that the deterioration of the battery 4 can be significantly suppressed. That is, conventionally, when the battery 4 is charged in a state where the voltage of the battery 4 is low, the charging current at the beginning of charging becomes a high current, and when the voltage of the battery 4 increases as the charging progresses, the charging current becomes low. Since the charger control circuit 1 according to the present embodiment controls the charging current at the beginning of charging to a constant current having a low current value, the burden on the battery 4 can be reduced.

  Since the charger control circuit 1 according to the present embodiment can substantially prevent the battery 4 from generating heat, it is not necessary to use a heat sink together with the switching power supply 2. Therefore, by using the charger control circuit 1, the size of the charger 3 can be reduced in size and weight. Moreover, as the switching power supply 2 included in the charger 3, various types of switching power supplies 2 can be used. Therefore, according to the charger control circuit 1 according to the present embodiment, the design freedom of the charger 3 can be secured widely, and the development cost of the charger 3 can be reduced.

Further, when the discharge voltage of the battery 4 is low or when the discharge rate of the battery 4 is low, the time until the battery voltage reaches V ₂ , the time until the charging current value reaches I ₂ , and / or the battery voltage Since the time from V ₂ to V ₃ is shortened, according to the charger control circuit 1 according to the present embodiment, the charging time can be shortened without applying an overcharge load to the battery 4.

  While the embodiments of the present invention have been described above, the embodiments described above do not limit the invention according to the claims. In addition, it should be noted that not all combinations of features described in the embodiments are necessarily essential to the means for solving the problems of the invention. Furthermore, the technical elements of the above-described embodiments may be applied independently, or may be applied by being divided into a plurality of portions.

DESCRIPTION OF SYMBOLS 1, 1a Charger control circuit 2 Switching power supply 3 Charger 4 Battery 10 Current control part 12 Current control cancellation part 14 Voltage control part 16 Voltage control cancellation part 18 Timer drive part 20 Charge maximum voltage control part 22 Charge stop part 24 Protection part 30 Main system 210 Contact 212, 214, 216, 218 Diode 220 Variable resistance 222, 224, 226, 228 Resistance 230 Polyswitch 232 Zener diode 234 Resistance 236 Relay coil 238 Relay 240 Voltage adjustment section 242 Supply stop section

Claims (11)

A charger control circuit for controlling operation of a charger for charging a battery,
A current control unit for charging the battery by controlling a charging current value to a predetermined first current value;
A current control release unit for releasing the control of the charging current value when the charging voltage reaches a predetermined voltage value;
After releasing the current control, a voltage control unit that charges the battery while maintaining the charging voltage at the voltage value;
A charger comprising: a voltage control canceling unit that cancels the control to be held at the voltage value when the charging current value of the battery reaches a predetermined second current value lower than the first current value; Control circuit. 2. The charger control circuit according to claim 1, further comprising: a timer driving unit that drives a timer that stops charging the battery after a predetermined time has elapsed after canceling the control to hold the voltage value. 3. The charger control according to claim 1, further comprising a charging maximum voltage control unit that preliminarily defines a maximum value of the charging voltage of the battery and controls the charging voltage to be equal to or less than the maximum value during charging of the battery. circuit. The charger control circuit according to any one of claims 1 to 3, further comprising a charge stopping unit that stops charging of the battery when the charging current value does not reach a predetermined current value or less.   The charger control circuit according to any one of claims 1 to 4, wherein the battery is used in an aerial work vehicle, a machine having power driven by electricity, or a special vehicle. The charger control according to any one of claims 1 to 5, further comprising a protection unit that stops supply of power to the battery when an input voltage input to the battery is equal to or higher than a predetermined voltage. circuit. The protective part is
When the input voltage is equal to or lower than a predetermined first voltage, the input voltage is used as an output voltage. When the input voltage is equal to or higher than a second voltage higher than the first voltage, the second voltage is increased. A voltage adjustment unit that uses the step-down voltage, which is the input voltage reduced accordingly, as the output voltage;
The charger control circuit according to claim 6, further comprising a supply stop unit that stops supply of power to the battery when the step-down voltage is equal to or lower than a predetermined threshold voltage.   A charger provided with the charger control circuit of any one of Claims 1-7, and a switching power supply. A charger control method for controlling operation of a charger for charging a battery,
A first charging step of charging the battery by controlling a charging current value to a predetermined first current value;
A current control release step of releasing the control of the charging current value when the charging voltage reaches a predetermined voltage value;
After the current control release step, a second charging step for controlling the charge voltage to be held at the voltage value and charging the battery;
A charger comprising: a voltage control canceling step for canceling the control held at the voltage value when the charging current value of the battery reaches a predetermined second current value lower than the first current value; Control method. A charge control program for a charger control circuit for controlling operation of a charger for charging a battery,
On the computer,
A first charging function for charging the battery by controlling a charging current value to a predetermined first current value;
A current control release function for releasing the control of the charge current value when the charge voltage reaches a predetermined voltage value;
A second charging function for controlling the charge voltage to be held at the voltage value after the control of the charge current value is released, and charging the battery;
Charging for realizing a voltage control release function for releasing the control held at the voltage value when the charging current value of the battery reaches a predetermined second current value lower than the first current value Control program.   A computer-readable recording medium on which the charge control program according to claim 10 is recorded.